#include <cstdio>
#include <vector>
#define nmax 100005

using namespace std;

vector<int> g[nmax],sol[nmax];
int n,m,nrc,niv[nmax],vf;
bool viz[nmax];
pair<int,int> st[nmax];

void citire()
{
    int x,y;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
}

void solutie(int x,int y)
{
    ++nrc;
    while(st[vf].first!=x&&st[vf].second!=y)
    {
        sol[nrc].push_back(st[vf].second);
        vf--;
    }
    sol[nrc].push_back(x);
    sol[nrc].push_back(y);
    vf--;
}

void dfs(int k,int tata,int nivel,int &niv_min)
{
    if(viz[k]==1)
        niv_min=niv[k];
    else
    {
        viz[k]=1;
        niv[k]=nivel;
        niv_min=nivel;
        int aux;
        for(vector<int>::iterator ii=g[k].begin();ii!=g[k].end();++ii)
        {
            if(*ii!=tata)
            {
                if(viz[*ii]==1)
                    dfs(*ii,k,nivel+1,aux);
                else
                {
                    st[++vf]=make_pair(k,*ii);
                    dfs(*ii,k,nivel+1,aux);
                    if(nivel<=aux)
                        solutie(k,*ii);
                }
                if(niv_min>aux)
                    niv_min=aux;
            }
        }
    }
}

void afisare()
{
    printf("%d\n",nrc);
    for(int i=1;i<=nrc;i++)
    {
        for(vector<int>::iterator ii=sol[i].begin();ii!=sol[i].end();++ii)
            printf("%d ",*ii);
        printf("\n");
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    citire();
    int aux;
    dfs(1,-1,1,aux);
    afisare();
    return 0;
}